As a first time user of this list, I should probably go through an
introduction before launching into the questions that I'd like to ask.
My name is Alastair, and I am presently reading for a bachelor's in
MicroBiology and Plant Pathology in the United Kingdom, where I live.
Though born in the United States, I am British, and have spent the greater
part of my life in Malaysia, most probably from whence my great interest in
unusual flora came about.
I am a comparatively recent introductee to the world of aroids, my real
expertise lying with the genus Nepenthes, and have been cultivating some of
the more freely available species of the genera Arum, Arisaema, Alocasia
and Colocasia with success.

I was recently in Chicago, where I was able to pick up a specimen of
Amorphophallus konjac, as well as one of Sauromatum venosum (Has this yet
been officially reduced to Typhonium?), being led to believe that both of
these are fairly hardy to Zones 6-7. It is with regard to their hardiness
that I require advice on as I would like to grow both of these out of
doors.

London is classified as Zone 8, though winter temperatures tend toward Zone
9 for the greater part. This would suggest that both of these plants
should fare quite well here. However, winters in the UK are pretty wet
when compared to those of the eastern United States, where many people seem
to grow these plants in the open. I would assume that overwintering in
such damp conditions would provoke the onset of rot - would anyone be able
to advise me to the contrary?
Further, springtime in this country can be very touch and go; while the
season decides what to do with itself, a warm spell might suddenly be
interrupted by a late frost or two which can damage the flowers and foliage
of many plants. Are these two susceptible to such damage, or are they
fairly resistant? If not, do they recuperate well from such an event?
I am uncertain as to how much soil (depth and volume) these plants, in
particular the Amorphophallus (which is immature and about 1' high) require
when mature. I would like to give the A.konjac a permanent position, and
have available a brick trough of dimensions 1'x1'x1.5'high with no base
(contact with ground loam and clay) - would this suffice? It is in a
fairly shaded spot and contains 3:1:1 humus, loam and grit.
Lastly, is there a particular depth that I should plant them at to protect
them from frost? Frosts locally don't seem to permeate more than two
inches into the soil, and so I would guess that a few more below that would
suffice.

I apologise for the mouthful, and hope that someone will be able to advise
me on these.
Thank you for your time and assistance :)